Instead of having to allocate a ~100 keys map containing possibly dynamic
values (at least to the go compiler), allocate it once in a global variable.
This significantly speeds things up, by reducing the garbage
collector/allocator involvements.
Local synthetic benchmarks have shown a improvements from 38% of wall time to only
12%.
- Use constant time access for maps instead of iterating on them
- Build a ~large whitelist map inline instead of constructing it item by item
(and remove a duplicate key/value pair)
- Use `slices` instead of hand-rolled loops
